Spurious Correlations

Which of the following correlates with the annual price of gold?

A: The base population of Fort Knox in Kentucky.

Bitcoin’s price has been relatively stable for the past few months, but last year saw a major downward trend plateauing earlier this year.
Five dollar bills printed by the Federal Reserve correlates with Motorcyclists killed in accidents in the U.S.
What do biology grad students do seven years out of school? They spend their billions at the casino, obviously!
The upward trend of the S&P 500 Index since 2009 bears a remarkable resemblance to the growth of legal lobbyists and litigators in the nation’s capital between 1999 and 2011.
In 2000, the average cost of a Big Mac was $2.51 and the average American consumed 7.7 gallons of whole milk...